Guide rail for railborne load carriers

ABSTRACT

In a guide rail (14) for railborne load carriers comprising a support (13) and at least one running rail (15) arranged in a groove (2) of the support (13), this support (13) is an extruded hollow profile. This results in a simple manufacturing method and a small material requirement.

The invention concerns a guide rail for railborne load carrierscomprising a support made as an extruded hollow profile and at least onerunning rail arranged in a groove of the support, a cavity of thesupport being divided into a lower and an upper chamber by a cross-web,while an outer wall of the lower chamber extends parallel to thecross-web.

A guide rail of this type is known from EP-B-0 213 160 and comprises twoparallel running rails mounted and fixed in parallel grooves of thesupport which are open towards the outside. These running railsconstitute raceways for rolling elements of a load carrier in the formof a carriage mounted slidably on the guide rail. The support in thecase of this known guide rail is a solid component so that aconsiderable amount of material is required for its manufacture. In themajority of uses, however, the rigidity offerred by solid guide rails isnot required, or the guide rail can be supported along its entire lengthso that reduced geometric moments of inertia do not have a negativeeffect.

CH-PS 557 483 discloses a device for the linear guidance of a machinecomponent comprising a guide rail of a hollow configuration. For thispurpose, an I-shaped support is surrounded by two profiled sheets of aparticular shape resulting in the formation of two cavities adjacent tothe profiled support. Two ball raceways are formed on the outer surfaceof each of these profiled sheets so that the sheets constitute a part ofa linear rolling bearing. Such guide rails have the disadvantage thatthe special configuration of the I-shaped support on both sides of itslength and, above all, the complicated shape of the profiled sheetsmakes it very expensive to manufacture.

A guide rail of the type initially mentioned is known from the documentDE-U-90 11 413. The support used therein comprises undercut longitudinalgrooves for lodging running rails. Access to these longitudinal groovesis from the inside of the upper chamber. In the region of each of theselongitudinal grooves for lodging running rails, there is provided in thesupport, another longitudinal groove which is accessible from theoutside and serves to connect the support to other parts of thestructure. These grooves therefore have to be precisely dimensioned. Ina transverse cross-section, this support has a substantially U-shapedconfiguration with the arms of the U extending upwards from thehorizontal crossbar. The upper chamber of this support is therefore onlyclosed on three sides and the fourth or upper side comprises alongitudinal slot. This support therefore does not possess the highrigidity of a closed hollow profile.

It is an object of the invention to provide a simple-to-manufactureguide rail for railborne load carriers and to configure the guide railso that material requirement is reduced.

The invention achieves this object by the fact that the upper chamberadjacent to the groove of the support is closed by a further outer wallof the support, which wall extends parallel to the cross-web. This upperchamber adjacent to the groove of the support can cooperate with agroove bottom of the groove to absorb a part of the plastic deformationtaking place during calibration.

A specially configured groove bottom of the two grooves in the guiderail for lodging the running rails permits calibration and thus alsoeconomic chipless manufacturing. Due to the cavities or chambers in thecalibration region, the extrusion molding manufacturing tolerance zoneof the support can be calibrated to the required size, the hollowprofile permitting a very high degree of plastic deformation of thesupport. The plastic deformation of the material of the support causedby the calibrating operation permits the running rails to extend at anexactly constant distance from each other in the grooves of thepreviously calibrated support along the entire length of the guide rail.If the running rails are rolled into the grooves, they have such a smalltolerance range that the carriage (load carrier) for this system can bemade with four central roller pins. The small tolerance range offers theadvantage that the guide rails can be manufactured economically byplaning which guarantees the exchangeability of the rails. The use offour central pins effects a cost reduction in the manufacture of thecarriage and has the advantage that the carriage can be fully adjustedby the manufacturer, and the user has only to push it onto the rail.

The fixing of the running rails in the grooves of the support does notnecessarily have to be effected by rolling-in. The grooves can also beconfigurd so that their U-arms are elastically displaceable outwards andretain the running rail by their restoring forces. The base region ofthe support comprises a central recess which increases the precision ofmounting because lateral stop surfaces in the base region of the supporthelp to obtain a better alignment of the guide rail during mounting.

Hollow profiles are easily available commercially in the form ofsemi-products and can be made, for example, of non-ferrous materials,particularly of an aluminium alloy. The running rail arranged and fixedin the groove of such a support can be made of steel or another highstrength, wear-resistant material. To obtain a reliable guidance of therailborne load carrier, two parallel running rails inserted into groovesof the support are used in most cases.

The cavity of the support is divided into an upper and a lower chamberby a cross-web. If several groups of aligned bores are provided in anouter wall of the upper chamber, in an outer wall of the lower chamberand in the cross-web, the guide rail can be fixed in a simple manner ona connecting structure by fixing screws inserted into the bores. In thiscase, the surface of the cross-web delimiting the upper chamber isadvantageously a flat surface which serves as a support surface for thescrew heads of the fixing screws.

Due to its configuration as a hollow profile, the guide rail of theinvention permits, for example, cables or wires of limit switches to berun through the chambers so that they are protected. The outwardly openbores for the fixing screws can easily be sealed by means of sealingcaps after insertion of the fixing screws. However, it is also possibleto fix the guide rail to the connecting structure by means of clampingelements which engage the base region of the guide rail. In this way,the chambers of the guide rail do not need to open outwards throughbores and can be used as pressure chambers.

Examples of embodiment of the invention are represented in the drawingsand will be described more closely below:

FIG. 1 is an end view of a first embodiment of a support for a guiderail,

FIG. 2 shows a second embodiment of a guide rail in a perspective view,and

FIG. 3 is an end view of the guide rail of FIG. 2.

The support 1 shown in FIG. 1 is made as a hollow profile with ony onegroove 2 for a running rail. The support 1 is divided into a lowerchamber 3 and an upper chamber 4 by a horizontal cross-web 5. An outerwall 6 of the lower chamber 3 and an outer wall 7 of the upper chamber 4extend parallel to the cross-web 5. A recess 8 is arranged below theouter wall 6 in the base surface 9 of the support 1, while severalgroups of aligned vertical bores are arranged at intervals along thecenter of the support 1 so that each bore 10 of the outer wall 7 isaligned with two bores 11 provided in the cross-web 5 and in the outerwall 6. A fixing screw can be inserted through each bore 10 into thechambers 4 and 3 of the support 1 to fix the support on the connectingstructure on which the base surface 9 rests. Facing the upper chamber 4,the cross-web 5 comprises a flat support surface 12 for supporting thescrew heads.

The support 13 of the guide rail 14 of the embodiment of FIGS. 2 and 3is basically of the same structure as the support 1 of FIG. 1. Thesupport 13, however, comprises two parallel grooves 2 for lodging twoparallel running rails 15. These grooves 2 likewise comprise a groovebottom which permits a plastic deformation (calibration) of the support13 upon insertion of the running rails 15. The upper chamber 4 permits avery high degree of plastic deformation for calibration and absorbs themajor part of the deformation.

    ______________________________________                                        List of Reference Numbers                                                     ______________________________________                                                  1   Support                                                                   2   Groove                                                                    3   Lower chamber                                                             4   Upper chamber                                                             5   Cross-web                                                                 6   Outer wall                                                                7   Outer wall                                                                8   Recess                                                                    9   Base surface                                                              10  Bore                                                                      11  Bore                                                                      12  Support surface                                                           13  Support                                                                   14  Guide rail                                                                15  Running rail                                                    ______________________________________                                    

We claim:
 1. A guide rail for railborne load carriers comprising a support (1, 13) made as an extruded hollow profile and at least one running rail (15) arranged in a groove (2) of the support (1, 13), a cavity of the support (1, 13) being divided into a lower chamber (3) and an upper chamber (4) by a cross-web (5), while an outer wall (6) of the lower chamber (3) extends parallel to the cross-web (5), characterized in that the upper chamber (4) adjacent to the groove (2) of the support (1, 13) is closed by a further outer wall (7) of the support (1, 13), which wall (7) extends parallel to the cross-web (5).
 2. A guide rail of claim 1 wherein the upper chamber (4) adjacent to the groove (2) of the support (1, 13) cooperates with a groove bottom of the groove (2) to absorb a part of a plastic deformation taking place during calibration.
 3. A guide rail of claim 1 wherein two or more parallel running rails (15) are arranged in grooves (2) of the support (13).
 4. A guide rail of claim 1 wherein the support (1, 13) is made of an aluminium alloy.
 5. A guide rail of claim 1 wherein the running rail (15) is a steel rail.
 6. A guide rail of claim 1 wherein the running rail (15) is made of a high strength wear-resistant material.
 7. A guide rail of claim 1 wherein a group of aligned bores (10, 11) for each one of a plurality of fixing screws is arranged in the outer wall (6) of the lower chamber (3), in an outer wall (7) of the upper chamber (4) and in the cross-web (5) of the support (1, 13).
 8. A guide rail of claim 1 wherein the cross-web (5) comprises a flat surface defining the upper chamber (4) and serving as a support surface (12) for screw heads of fixing screws. 